S608-2RS Sealed Ball Bearing 8 x 22 x 7 mm S608-2RS Ceramic Skate Bearing are double sealed, radial and deep groove ball bearings, they categorized as low friction 8mm axle skate bearing,S608-2RS bearings are made of Stainless Steel with Si3N4 Ceramic (Silicon Nitride) balls, S608-2RS bearing are closed with rubber seals to protect the bearing from dust or any possible contamination,Bearing work in skateboards, longboards, inline skates, rollerblades and roller hockey, Bearings are ABEC-5 quality to ensure high speeds.